*{
    margin: 0;
    padding: 0;
}
ul,ol{
    list-style: none;
}
img{
    display: block;
}
a{
    text-decoration: none;
    color: brown;
}
body{
    font-family: Arial, Helvetica, sans-serif;
}
.l{
    float: left;
}
.r{
    float: right;
}
.clear::after{
    content: "";
    display: block;
    clear: both;
}
.comm{
    width: 820px;
    margin: 0 auto;
}
.center{
    text-align: center;
    font-size: 30px;
}